Abstract
Penetration into human erythrocytes of acyl-TDS and O-acylthiamine was investigated in vitro. TDS added to the erythrocytes suspension was hardly reduced to free thiamine, and it was deduced that the rate limiting factor was its low permeability. While the lipophilic derivatives, BTDS, CTDS, BuTDS etc., were rapidly reduced under the first order kinetics, showing their high permeability by simple diffusion mechanism. Penetration of O-acylthiamines, OBuT, OVT, OCT and OBT, were measured in DFP-added erythrocytes suspension (to exclude intracellular deacylation of the vitamins), and their rapid influx and outflux were also revealed kinetically. These findings were compared and discussed with old knowledges obtained by static or usual "washing" procedure.
